Over the last few days, the webpage that I'm using will freeze and the top left of the screen displays the message 'not responding' and I then have to recover the page.
This is now happening on a regular basis - I've checked for and installed important updates as recommended by Windows Help section, but that hasn't solved the problem.
Which version of IE9 are you using ? If you are using the 64 bit version of Windows 7 then you must use the 32 bit version of IE9 as the other is not stable. You could head over to Tools and Internet Options click on the advanced tab and see if the Graphics acceleration is ticked for software and not hardware if you dont have a graphics ard installed and are using the on bpard one. A complete removal and reinstall has been a good fix for this problem in the past.
Further to my previous post it would be a good idea to check your add ons by going to Tools and click on manage add ons check too see if there is any rogue ones there and delete them also check the others and see if you need them delete if dont and check the load times .Disable the ones that are taking a long time too load.